Technology: What is in the Sorghum Pipeline...Dhurrin Content in Sorghum (Sorghum bicolor L. Moench)...
Transcript of Technology: What is in the Sorghum Pipeline...Dhurrin Content in Sorghum (Sorghum bicolor L. Moench)...
Technology: What is in the Sorghum Pipeline
Zhanguo Xin Gloria Burow Chad Hayes Yves Emendack
Lan Liu-Gitz, Halee Hughes, Jacob Sanchez, DeeDee Laumbach, Matt Nesbitt
ENVIRONMENTAL CHALLENGES REDUCE YIELDS AT EVERY STAGE OF DEVELOPMENT
Data Items 2011 2010
SORGHUM - ACRES PLANTED 5,451,000 5,369,000
SORGHUM, GRAIN - ACRES HARVESTED 3,945,000 4,806,000
SORGHUM, GRAIN - YIELD, BU / ACRE 54 71.9
Source: NASS
Germplasm Evaluation:Drought Tolerance:
Pre-Flowering TolerancePost-Flowering Tolerance
Cold Tolerance:GerminationVigor
Irrigation SchedulingGermplasm Development:
Photoperiod Sensitivity ConversionDevelopment of RIL populations for Cold ToleranceDevelopment of Novel Inbred Lines with Improved YieldsDevelopment of Annotated Gene Discovery Population
Improving Stand Establishment
Ethiopian Cold Tolerance
2,000 125 25
Cold GerminationField Germination & Vigor
COLD GERMINABILITY OF GERMPLASM
Cold Germination at 12 C for 72 h
April 10
April 11
April 30
2013
2015
Chinese Cold Tolerance RIL Populations
RTx430 x Gai Gaoliang (Released)BTx623 x Kaoliang (Ready for Release)BTx623 x Hong Ke Zi (Ready for Release)BTx623 x Niu Sheng Zui (1 Year Out)
Quantitative Trait Loci have been identified for cold germination and early season vigor.
Burow GB, Burke J., Franks CD, Xin, Z, 2011. Genetic dissection of early-season cold tolerance in sorghum (S. bicolor). Mol. Breeding, 28:391-402
Stand Establishment on Marginal Soils
We have recently identified a metabolic marker in sorghum that correlates with biomass accumulation on low nitrogen soils during the first three weeks following emergence.
Summary
• We have identified sorghum lines with excellent germination at low temperatures.
• We have identified sorghum lines with excellent vigor at low temperatures.
• We have mapped quantitative trait loci for cold tolerance during germination.
• We have identified a metabolic marker that correlates with improved seedling development in marginal soils having low nitrogen levels.
Improving Drought Tolerance
EARLY SEASON MOISTURE
Seasonal Rainfall Patterns
LATE SEASON MOISTURE
VARIABLE SEASON MOISTURE
EARLY SEASON MOISTURE
Seasonal Rainfall Patterns
LATE SEASON MOISTURE
VARIABLE SEASON MOISTURE
Post-Flowering Drought Tolerance
Pre-Flowering Drought Tolerance
Pre- and Post-Flowering Drought Tolerance
Symptoms of pre-flowering drought stress: leaf rolling, uncharacteristic leaf erectness, leaf bleaching, leaf tip and margin burn, delayed flowering, saddle effect, poor panicle exsertion, panicle blasting and floret abortion, and reduced panicle size.
Post-flowering water-deficit stress can have direct effects on grain size, as well as effects on harvest due to premature plant death, increased susceptibility to charcoal rot, and lodging, all of which effect yield potential.
Sorghum Responses to Drought
PRE - POST-
SCENECENT STAY-GREEN
SORGHUM DROUGHT TOLERANCE BIOASSAY DEVELOPED
Researchers at the Cropping Systems Research Laboratory developed an assay to identify “stay-green” sorghums without the requirement of post flowering water stress.
Dhurrin Determinations:Conversion Panel BTx623 * Niu Sheng Zui RILsAssociation Panel CSRL Breeding LinesBTx 642 * Tx7000 RILs AIMS LinesSC 56 * Tx7000 RILs Industry LinesEthiopian Collection Sudanese LinesKSU RILs
Leaf Dhurrin Content is a Quantitative Measure of the Level of Pre- and Post-flowering Drought Tolerance in Sorghum. Crop Sci. 53:1056–1065
Post-Flowering Tolerance
Pre-Flowering Tolerance
Pre- and Post-Flowering Tolerance
Dhurrin
Natural Variation in Synthesis and Catabolism Genes Influences Dhurrin Content in Sorghum(Sorghum bicolor L. Moench)
Genome-wide association analysis (GWAS) using a panel of 700 diverse converted sorghum lines.
Genes for biosynthesis and catabolism are important in determiningnatural variation for leaf dhurrin in sorghum in different environments.
BTx642/Tx7000 RIL QTL
Stay-green (1993-1998) and Dhurrin
Sudanese Stay-Green
367 8 3
Efficiency of Quantum YieldDhurrin levels
Ethiopian Stay-Green
2,000 125
Efficiency of Quantum YieldMaintenance of lower leaves under low lightDhurrin levels
22
Conversion of Photoperiod Sensitive Stay-Green Ethiopian Lines
Post-Flowering Tolerance
Pre-Flowering Tolerance
Pre- and Post-Flowering Tolerance
Dhurrin
Summary
• We have identified a relationship between leaf dhurrin levels and the level of post-flowering drought tolerance.
• We have identified the chromosomal regions associated with dhurrin accumulation and turnover.
• We have identified and released lines with pre-and post-flowering drought tolerance.
Sorghum Gene Discovery Population for Trait Improvement
We have developed technology to move from Quantitative Trait Loci (QTLs) to specific gene identification and subsequent development of perfect trait markers for molecular assisted breeding.
Sorghum Gene Discovery Population for Trait Improvement
F1
Pooled F2 plants homozygous for target trait
Background SNPs
Target Trait Gene
Other Genes
✕
BTx623 Plant with target trait
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Yield
Protein Content
Protein Digestibility
Mineral Content (Iron, Zinc, etc.)
Sorghum Gene Discovery Population for Trait Improvement
MODERN SORGHUM HYBRIDS DO NOT SET SEED AT EVERY FLOWER!!!
Traits of Interest:
Yield
Traits of Interest:
Yield
Sorghum Gene Discovery Population for Trait Improvement
Screen Gene Discovery Population for Multi-seed Trait
Sorghum Gene Discovery Population for Trait Improvement
F1
Pooled F2 plants homozygous for msd trait
Background SNPs
Mutli-seedTrait Gene
Other Genes
✕
BTx623 Plant with msd trait
Sorghum Gene Discovery Population for Trait Improvement
Having identified the gene controlling the multiseed trait, we create msd gene specific markers for molecular breeding.
Screen segregating populations of inbredsused for hybrid production for the homozygous msd gene.
msd
Wild Type
Heterozygous
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
YieldWe can now move the multi-seed trait into any sorghum line.
Seed with this trait has been provided to seven sorghum seed companies.
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Yield ✓
Protein Content
Protein Digestibility
Mineral Content (Iron, Zinc, etc.)
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Protein Content
Screen Gene Discovery Population for Protein Content
Scott Bean, ARS, Manhattan, KS
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Yield ✓
Protein Content ✓
Protein Digestibility
Mineral Content (Iron, Zinc, etc.)
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Protein Digestibility
Screen Gene Discovery Population for Protein DigestibilityScott Bean, ARS, Manhattan, KS
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Yield ✓
Protein Content ✓
Protein Digestibility ✓
Mineral Content (Iron, Zinc, etc.)
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:Mineral Content (Iron, Zinc, etc.)
Mike Grusak 2014
02468
10121416
Zn
02468
1012141618
Fe
Sorghum Gene Discovery Population for Trait Improvement
Traits of Interest:
Yield ✓
Protein Content ✓
Protein Digestibility ✓
Mineral Content (Iron, Zinc, etc.) ✓
Summary
• The gene discovery library possesses many beneficial traits for sorghum improvement.
• An efficient pipeline has been established to identify genes underlying important traits.
• The sequenced population covers over 93% of the genes, enabling in sillico identification of the population for important genes.
Special thanks to the Sorghum Checkoff Program for their support of this research.